// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "cc/raster/raster_buffer_provider.h"

#include <stddef.h>

#include "base/trace_event/trace_event.h"
#include "cc/playback/raster_source.h"
#include "cc/raster/texture_compressor.h"
#include "cc/resources/platform_color.h"
#include "cc/resources/resource_format_utils.h"
#include "third_party/skia/include/core/SkCanvas.h"
#include "third_party/skia/include/core/SkSurface.h"

namespace cc {

RasterBufferProvider::RasterBufferProvider() { }

RasterBufferProvider::~RasterBufferProvider() { }

namespace {

    bool IsSupportedPlaybackToMemoryFormat(ResourceFormat format)
    {
        switch (format) {
        case RGBA_4444:
        case RGBA_8888:
        case BGRA_8888:
        case ETC1:
            return true;
        case ALPHA_8:
        case LUMINANCE_8:
        case RGB_565:
        case RED_8:
        case LUMINANCE_F16:
            return false;
        }
        NOTREACHED();
        return false;
    }

} // anonymous namespace

// static
void RasterBufferProvider::PlaybackToMemory(
    void* memory,
    ResourceFormat format,
    const gfx::Size& size,
    size_t stride,
    const RasterSource* raster_source,
    const gfx::Rect& canvas_bitmap_rect,
    const gfx::Rect& canvas_playback_rect,
    float scale,
    sk_sp<SkColorSpace> dst_color_space,
    const RasterSource::PlaybackSettings& playback_settings)
{
    TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("cc.debug"),
        "RasterBufferProvider::PlaybackToMemory");

    DCHECK(IsSupportedPlaybackToMemoryFormat(format)) << format;

    // Uses kPremul_SkAlphaType since the result is not known to be opaque.
    SkImageInfo info = SkImageInfo::MakeN32(size.width(), size.height(),
        kPremul_SkAlphaType, dst_color_space);

    // Use unknown pixel geometry to disable LCD text.
    SkSurfaceProps surface_props(0, kUnknown_SkPixelGeometry);
    if (raster_source->CanUseLCDText()) {
        // LegacyFontHost will get LCD text and skia figures out what type to use.
        surface_props = SkSurfaceProps(SkSurfaceProps::kLegacyFontHost_InitType);
    }

    if (!stride)
        stride = info.minRowBytes();
    DCHECK_GT(stride, 0u);

    switch (format) {
    case RGBA_8888:
    case BGRA_8888: {
        sk_sp<SkSurface> surface = SkSurface::MakeRasterDirect(info, memory, stride, &surface_props);
        raster_source->PlaybackToCanvas(surface->getCanvas(), canvas_bitmap_rect,
            canvas_playback_rect, scale,
            playback_settings);
        return;
    }
    case RGBA_4444:
    case ETC1: {
        sk_sp<SkSurface> surface = SkSurface::MakeRaster(info, &surface_props);
        // TODO(reveman): Improve partial raster support by reducing the size of
        // playback rect passed to PlaybackToCanvas. crbug.com/519070
        raster_source->PlaybackToCanvas(surface->getCanvas(), canvas_bitmap_rect,
            canvas_bitmap_rect, scale,
            playback_settings);

        if (format == ETC1) {
            TRACE_EVENT0("cc",
                "RasterBufferProvider::PlaybackToMemory::CompressETC1");
            DCHECK_EQ(size.width() % 4, 0);
            DCHECK_EQ(size.height() % 4, 0);
            std::unique_ptr<TextureCompressor> texture_compressor = TextureCompressor::Create(TextureCompressor::kFormatETC1);
            SkPixmap pixmap;
            surface->peekPixels(&pixmap);
            texture_compressor->Compress(
                reinterpret_cast<const uint8_t*>(pixmap.addr()),
                reinterpret_cast<uint8_t*>(memory), size.width(), size.height(),
                TextureCompressor::kQualityHigh);
        } else {
            TRACE_EVENT0("cc",
                "RasterBufferProvider::PlaybackToMemory::ConvertRGBA4444");
            SkImageInfo dst_info = info.makeColorType(ResourceFormatToClosestSkColorType(format));
            bool rv = surface->readPixels(dst_info, memory, stride, 0, 0);
            DCHECK(rv);
        }
        return;
    }
    case ALPHA_8:
    case LUMINANCE_8:
    case RGB_565:
    case RED_8:
    case LUMINANCE_F16:
        NOTREACHED();
        return;
    }

    NOTREACHED();
}

bool RasterBufferProvider::ResourceFormatRequiresSwizzle(
    ResourceFormat format)
{
    switch (format) {
    case RGBA_8888:
    case BGRA_8888:
        // Initialize resource using the preferred PlatformColor component
        // order and swizzle in the shader instead of in software.
        return !PlatformColor::SameComponentOrder(format);
    case RGBA_4444:
    case ETC1:
    case ALPHA_8:
    case LUMINANCE_8:
    case RGB_565:
    case RED_8:
    case LUMINANCE_F16:
        return false;
    }
    NOTREACHED();
    return false;
}

} // namespace cc
